The present invention relates to a deposition head arrangement for depositing particles onto a semiconductor wafer in particular, under a controlled sequence, so that the location, and amount of the particle deposition can be precisely controlled.
In the prior art, it has been known to use an aerosol carrying particles that are deposited onto semiconductor wafers and other substrates in a deposition chamber. The controlling of the density and location of such particles is of great importance, and in many instances it is desirable to deposit individual spots of particles on a wafer as well as providing full coverage of the wafers. It has also been known to apply an electrical charge between a deposition head and the wafer or substrate.
It also has been known to rotate the support tables used in deposition chambers while a thin film material is introduced into the chamber, but in general the rotation has been used primarily for a uniform coating across a wafer that is supported on the table. Such a rotatable device is shown in U.S. Pat. No. 5,688,565 for example.
It is also been known to provide a potential between the deposition head and the support table that supports the wafer, for attracting the particles that are being deposited to the wafer or substrate, in order to insure control the deposition area.
However, precise control of not only the size of the area covered by the particles but also the location of the particles on a wafer is still desired.
The present invention relates to an aerosol deposition head that can be moved relative to a rotating wafer or substrate in a deposition chamber. The deposition head has two different size discharge openings for discharging particles. The head provides precise sizing of the deposition areas. The rotating support and movable deposition head are controlled to properly place the particles on the substrate.
The apparatus used for the present invention includes a rotating support table for the substrate on which deposition is to be made. The deposition head has a central relatively small tubular discharge opening and a larger annular discharge opening surrounding the central opening. The deposition head is mounted on a support on a deposition chamber and the deposition head will move radially linearly perpendicular to the rotational axis of the substrate carrier. The line of movement of the deposition head is along an axis that intersects the rotational axis of the rotating substrate character.
The present apparatus thus provides for precisely controlling the deposition of particles in desired spots on a substrate, or permits full coverage of the substrate in a uniform layer, or permits irregular patterns to be deposited by controlling the relative rate of rotation of the substrate holder and the linear movement and position of the deposition head while also controlling the flow of the deposition material, both as to the rate of flow and whether the flow is on or off.